Controlling the fan on a Dell

A couple of days ago the fan on my Dell Latitude D410 (running Ubuntu Hardy) started behaving strangely.

Once the fan started up it would stay on. Very annoying.

I did the usual checking for runaway processes but there were no such problems.

So I then checked the CPU temperature:

   cat /proc/acpi/thermal_zone/THM/temperature

Next I discovered that the sensors screenlet can be used to display the temperature.

Watching this the cpu temperature steadily rose, the fan clicked in, the cpu cooled but the fan never shuts down.

A bit of googling looking for others with the same laptop and this problem came up with the dellfand project.

This is a simple daemon to control the fan on Dells. Works great, and now I can control just what temperatures the fan clicks in, goes into high speed and shuts off.

I'm still puzzled what broke/changed the other day, but at least for now I can control the problem.

OpenSSL security issue and Ubuntu response

The big news of the day is the openssl security issue with debian based systems.

A bit of an embarrassing story, the code involved in generating keys was patched to stop valgrind complaining about some uninitialised memory.

Unfortunately, this resulted in less entropy feeding into the key generation (as far as I can gather) and so there is an easy attack on the vulnerable keys.

Now whilst this is unfortunate, I think some praise is due to the way Ubuntu has handled the issue. After hearing about the problem this afternoon, I just fired up the update-manager and checked for updates.

Sure enough, there was a full set of openssl and ssh related updates to install.

I installed these and was greeted with a helpful dialogue which explained that the host key on my machine was one of the weak ones and had been regenerated. Further, it pointed me at a new command, ssh-vulnkey which can be used to check for bad keys.

So, whilst it is more than a little unfortunate that this problem has been around 2 years, kudos for getting out the fix so quickly and for the pain free way it has been rolled out.

Prism apps in Hardy Heron

I've been using the Google Prism apps since moving to Ubuntu Hardy.

This blog has a good summary of how to install these applications in Hardy and what they are good for.

The short version is that prism runs web based applications as standalone applications.

I've found these prism apps a mixed experience. On the plus side, having gmail, google reader and the like separate from the browser is handy:

• No longer accidentally closing the tab for one of these


• More real estate for the application


• Icons in the panel for the individual applications


• Able to launch the apps from launchers such as gnome-do

The big down side is that you no longer get all the functionality that you get in the browser. For example, keyboard accelerators to increase/decrease font sizes. On the other hand, this can be a good thing if the web application itself is really well designed, since it is no longer restricted to the key and mouse events that the browser doesn't grab.

One other down side I've found is opening links from these apps. Sometimes they open a new prism window, sometimes they open in my browser. I haven't quite figured out how to control all this and it can be annoying not being sure where and how things are going to open.

Hardy Heron goodness

I've been using the Hardy Heron betas for several weeks now and it has been a joy to use.

I used a different strategy to previous Ubuntu upgrades. This time I did a fresh install with a fresh home directory (in a separate partition) too. I then created links to the key directories in my old home directory. In this way I was able to use Hardy, without worrying about clobbering old config files and so have been using on the machine (Dell Lattitude D410) I use for work.

Some highlights:

• xrandr at work I dock the laptop and have a 1280x1024 screen. This is the first release where I have been able to suspend the laptop, head into work, issue a few commands and have the X session change resolution and use the external monitor. Added bonus I can get it to use the laptop as a secondary display, all using compiz fusion.
  
• gnome-do I'm finding this really useful and fun to use. Love the way it spots the things you frequently launch. After using it for a few weeks most of the common things I launch can be fired up in 2-3 key pushes
  
• tracker I've tried google desktop and beagle in the past, but found them hogging resources too much. Tracker seems to be indexing stuff well without hogging the cpu
• pulse audio is the new sound server in Hardy. I don't know too much about it, but one feature I really like is you can use it to configure machines to enable network access to the server. Other machines on the network using pulse detect available servers and you can then use any available machine as the sound sink. To configure this I had to aptitude install pavucontrol and fire it up. This gives you an icon in the notification area that you can use to select the sound sink. So I can now play music on the laptop and have the sound use the decent speakers on my desktop system.
• firefox3.0, much snappier than 2.0.